The present disclosure generally relates to reducing performance degradation due to simultaneous switching noise.
Integrated circuit devices communicate with one another using input/output (I/O) circuits that are configured to transmit and receive multi-bit data over a plurality of signal lines forming a bus. When multiple output drivers on the circuits change state at the same time at a high speed to transmit the multi-bit data, the changing current drawn by the output drivers from a power supply induces a voltage that results in power supply disturbance, commonly referred to as simultaneous switching output (“SSO”) noise (or simultaneous switching noise (“SSN”)).
SSN can cause undesired behavior in the receiver side of the integrated circuits, especially in a system that communicates the data using single ended signaling. Modern receivers using single ended signaling compare the data signal received over the signal lines with a reference voltage to determine the logic level (“1” or “0”). If SSN is induced in the data signal transmitted to the receiver, the data signal may be at a voltage level different from the prescribed voltage level for single ended signal that would ensure a sufficient margin between the voltage level and the reference voltage used for comparison with the data signal, and thus result in signaling error.